Effect of viscosity on learned satiation

A higher viscosity of a food leads to a longer orosensory stimulation. This may facilitate the learned association between sensory signals and metabolic consequences. In the current study we investigated the effect of viscosity on learned satiation. In two intervention groups a low viscosity (LV) yogurt (n = 24) and a high viscosity (HV) yogurt (n = 22) was offered ad libitum for breakfast. In a learning period of 4 weeks, subjects consumed ad libitum a novel flavoured high energy density (HED) yogurt (150 kcal/100 g) or low energy density (LED) yogurt (50 kcal/100 g), with 10 exposures to each yogurt on alternate days. Over the repeated exposures, an interaction effect of exposure time * energy * viscosity on intake was seen (F(1,771) = 4.12; p = 0.04). In the HV intervention group a borderline significant interaction between exposure and energy density was observed (F(1,369) = 3.61; p = 0.06); after 10 exposures, the LED yogurt resulted in a 46 ± 16 g higher intake compared with the HED yogurt. In the LV group, no significant interaction between exposure and energy density was seen (F(1,401) = 1.04; p = 0.31); after 10 exposures intake difference between the LED and HED yogurts was only 1.5 ± 15 g. These results suggest that a higher viscosity facilitates learned satiation. © 2009 Elsevier Inc. All rights reserved.